1.6 Special Pairs of Angles
Sep 23rd, 2011 by corricelli
Hello!
Use this page to post questions related to section 1.6, Special Pairs of Angles.
HW due Monday: Read and take notes on pages 44-46 in the textbook. Do page 47: #s 1-7.
HW due Tuesday: page 47: 9, 13, 15, 17, 21, 25, 29-37 odd, 45, 49, 53
PLEASE BRING YOUR TEXTBOOK ON MONDAY!!!
Thank you!
Happy blogging,
Mrs. Corricelli
The lab activity really helped today. It made everything clearer and I got better at recognizing all of the angles that add up to 360 degrees. I hope we can do more interactive projects in the future!
~Kerry
I’m having trouble with question 35 on the hw. Can someone explain how you do it? I got confused since in this question it has 2 congruent angles but different letters.
An,
Consider “forcing” an equation with only x. Would a linear pair work? No – as you wrote, you would end up with two unknowns. Try vertical angles… Mmm can you set two equations equal to each other because they are vertical angles?
Let me know your progress. Show some more work and I can help.
Mrs. Corricelli
Hello,
I’m a bit confused on how to do problems 29-35 odd.
Are we supposed to make it an equation?
Thank you,
Charlie
Charlie,
Consider Example 3 in the book and the example we did in class. These are more basic examples than the one we did together. Let’s look at 29 together:
So on 29, notice how the two angles with measures share a ray and form a line; they are a linear pair!
Therefore, their measures add to 180 degrees.
Use this to set up an equation.
In 30, however, the angles are vertical angles so the given equations would be set equal to each other.
Show me your work on 29 (so far) and I will continue to guide more if need be.
Happy blogging,
Mrs. Corricelli
Hi, so I’m doing the quiz corrections, and I don’t remember the layout you wanted…did you want the original problem, then the correct answer, then an explanation?
Amy,
Number each question and then write the correct answer next to the number. Then show work and/or words to show new learning.
We will go over any pending questions in class tomorrow.
Thanks for posting!
Mrs. Corricelli
for number 45 i know the angle measures have to add up to 90 but im not sure how to write out the problem
Shane,
Start with what you just typed…
You said…
“The angle measures have to add up to 90″
In alg/geo, this means,
meas of angle A + meas of angle B = 90 (sorry; cannot type angles for some reason).
So… write using expressions involving x.
Now go forward and do amazing algebra!
Happy algebra-ing,
Mrs. Corricelli
I am having a little trouble figuring out how to do numbers 43 and 53.. Can anyone help me on those ?
Hi,
I just wanted to comment that I like the new set-up on the website (when you hover the tabs). Thanks!
Hi,
so for the homework tonight on the worksheet, im having trouble doing number 13. i dont know if how you are supposed to set up each equation. I set up the equation like this:
5y+10+6y-2=180 but when i solve it, it comes out to a decimal. So im not sure if i should set each one up to 180 like this:
5y+10=180 and then 6y-2=180 and then solve for both.
Libby,
Look carefully at the diagram and then let’s check out your two approaches:
Approach 1
Is it true that vertical angles must sum to 180 degrees? When you wrote, “5y+10+6y-2=180″, you took two expressions for vertical angles and added them to get 180 degrees. Think back to the lab. When moving the line, you noticed (astutely) that vertical angles are equal. They could each be 20 degrees or 100 degrees. There is no promise that adding them together will give you 180 degrees.
Approach 2
Is it true that each vertical angle must equal 180 degrees? When you wrote, “5y+10=180 and then 6y-2=180″, you assumed that each of the two vertical angles was guaranteed to be 180 degrees. Think back to the lab. When moving the line, you noticed that vertical angles are equal in measure. They could each be 20 degrees or 100 degrees. There is no promise that one of them alone will be 180 degrees. Also, if they were, would there be two lines anymore?
Now, consider the notes or book. What does it mean when two angles are vertical? Only one thing: that their measures are equal. So…
5y + 10 = 6y – 2 is the only legal expression.
Please reply if this makes sense or not. Thank you for posting… I am sure that there are teammates, near and far, with these types of questions. You are truly helping them to understand.
Happy angling,
Mrs. Corricelli
i had trouble on quetion 13 too i got 18 2/3 but when i did 110=2x+40 i got 110 and somehow i got 110 for the other three
Kayla and Libby,
Let’s look at 13 together:
110 = 2x + 40 is totally legal. Subtracting 40 from each side changes the equation to 70 = 2x. Then, dividing each side by 2, x = 35. I am a little confused when you said that you “got 110 for the other 3″. Since this angle is 110, this means the supplement is 70. Therefore, 70 = either 6y – 2 or 5y + 10. Alternatively, you could not trust your result for x and work exclusively with y (and vertical angles). So 5y + 10 = 6y – 2 should give y = 12.
Let me know if this helps and/or your results on the others…
Happy Angling,
Mrs. Corricelli
on question 5-8, do 9+8 have to equal 180 degrees? and same with 6+7?
Mike,
Yes! (meas of angle 6) + (meas of angle 7) = 180 degrees because they are a linear pair. The same with angles 9 and 8.
Assume that each problem creates a whole new picture. The angle measure for angle 7 in number 5 need not be the same as it is for number 7.
Happy Geometry-ing,
Mrs. Corricelli
Hi Mrs. Corricelli
sorry im just getting back to you but i completley understand what you explained to me and i see what i did wrong.
Thank you!
i had i little trouble with number 35and 45 but after we when over it in class i understand it better
Kevin,
Great! Now…
Can you be more specific? What new learning helped? What was said in class that helped you to understand? What did you do correctly and/or incorrectly? These are the types of reflections that will most help a teammate and yourself to grow… Can you answer one/all of these?
Happy Thursday,
Mrs. Corricelli
i am doing the review packet for mondays test and im having trouble on a problem. On the second page of the packet, Chapter Test C, im having trouble on 29 and 30. I got x for number 29 but i cant figure out how to get y
Libby,
So – now that you have x, you know (x’s value) + (2y – 17) must equal 180 because they form a linear pair. One unknown; one equation – all set!
Let me know,
Mrs. Corricelli
okay thank you i understand that! but now i am confused on 30. So i got x….x=17.5 and then i tried to do what you said to do in #29 so i did 2y-17+17.5+17.5=180 but i didnt get the write answer. I did 17.5 +17.5 because there are two open angles that arent labeled. but im still confused on how to get y
Libby,
Do you see how y’s expression is part of a pair of vertical angles? So…. 2y – 17 = 40? Does this make sense?
Mrs. Corricelli
okay I actually understand how to get y. i got the answer to y by setting up the equation 2y-17+70+4x=180. i got y=28.5. so the angles across from each other are equal. But how do you check if it all adds up to 180?
o okay i get it now! thank you. sorry about all the questions!
ok so basically supplementary angles are angles that equal 180. So anytime they give you a given degreee and they as for another angles degree , your subtract that number from 180, right ? An example, if M<1 = 40 , what is the measure of angle two if it is supplementary. You would then do, 180-40= 140 which would give you the measure of angle. inj matematical terms M<1 = 40 + M<2= 140 which gives you 180.. the supplementary . am i wrong ?